1. A pair of osmodes will be implanted astraddle the preoptic and hypothalamic nuclei of the adelie penguin to infuse hypertonic and hypotonic solutions of NaCl. The secretion of the nasal salt gland will be collected while NaCl is infused into the gut or intravenously at a constant rate. 2. The effects on salt gland secretion in response to IV infusion of mannitol and isosorbital in a penguin receiving a continuous gastric infusion of NaCl will be studied. 3. The effects of infusing non-adrenalin, prostaglandin E, and angiotensin II on shivering and salt gland secretion respectively will be obtained in the penguin. 4. Two pair of thermodes will be implanted astraddle the preoptic and hypothalamic nuclei of the adelie penguin and peking duck reared on 1 percent NaCl solution. During a continuous IV infusion or gastric injection of a NaCl solution, the effects of heating and cooling the brainstem nuclei upon nasal salt secretion and water ingestion will be measured. 5. The possible role of thermal osmosis will be assessed as a factor in the thermal effects of brainstem temperature on osmo-regulatory responses. BIBLIOGRAPHIC REFERENCES: Simon, E., H.T. Hammel, Ch. Simon-Opermann, R. Kaul and J. Maggert. Role of rostral brain stem thermosensitivity in temperature regulation of the adelie penguin. Pflugers Archiv. Eur. J. Physiol. Suppl. 359: R57, 1975. Simon-Opermann, Ch., H.T. Hammel, E. Simon, R. Kaul and J. Maggert. Role of spinal cord thermosensitivity in temperature regulation of the adelie penguin. Pflugers Archiv. Eur. J. Physiol. Suppl. 359: R57, 1975.